From patchwork Fri Feb 7 03:37:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Hubbard X-Patchwork-Id: 11369719 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C525B14E3 for ; Fri, 7 Feb 2020 03:38:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A385022522 for ; Fri, 7 Feb 2020 03:38:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="BCVsa9Vg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727561AbgBGDhk (ORCPT ); Thu, 6 Feb 2020 22:37:40 -0500 Received: from hqnvemgate25.nvidia.com ([216.228.121.64]:13345 "EHLO hqnvemgate25.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727527AbgBGDhj (ORCPT ); Thu, 6 Feb 2020 22:37:39 -0500 Received: from hqpgpgate102.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Thu, 06 Feb 2020 19:37:12 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate102.nvidia.com (PGP Universal service); Thu, 06 Feb 2020 19:37:37 -0800 X-PGP-Universal: processed; by hqpgpgate102.nvidia.com on Thu, 06 Feb 2020 19:37:37 -0800 Received: from HQMAIL107.nvidia.com (172.20.187.13) by HQMAIL109.nvidia.com (172.20.187.15) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Fri, 7 Feb 2020 03:37:37 +0000 Received: from hqnvemgw03.nvidia.com (10.124.88.68) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Fri, 7 Feb 2020 03:37:37 +0000 Received: from blueforge.nvidia.com (Not Verified[10.110.48.28]) by hqnvemgw03.nvidia.com with Trustwave SEG (v7,5,8,10121) id ; Thu, 06 Feb 2020 19:37:36 -0800 From: John Hubbard To: Andrew Morton CC: Al Viro , Christoph Hellwig , Dan Williams , Dave Chinner , Ira Weiny , Jan Kara , Jason Gunthorpe , Jonathan Corbet , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , "Kirill A . Shutemov" , Michal Hocko , "Mike Kravetz" , Shuah Khan , "Vlastimil Babka" , Matthew Wilcox , , , , , , LKML , John Hubbard , "Kirill A . Shutemov" Subject: [PATCH v5 06/12] mm/gup: require FOLL_GET for get_user_pages_fast() Date: Thu, 6 Feb 2020 19:37:29 -0800 Message-ID: <20200207033735.308000-7-jhubbard@nvidia.com> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200207033735.308000-1-jhubbard@nvidia.com> References: <20200207033735.308000-1-jhubbard@nvidia.com> MIME-Version: 1.0 X-NVConfidentiality: public DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1581046633; bh=zdKJN+80LnhrM42H0YcEzysuucpfBmwOwmXaeST0eWY=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:X-NVConfidentiality: Content-Transfer-Encoding:Content-Type; b=BCVsa9Vg/FLx131VkBwVusgApBWD3rXCMU4HwFYgqK+JHpePFTfpxlV7oG9uqvwoD eFInmWS/uaWR2xl9VFdCBWhGrmcdqU43SUDY+MjXrnqfaP1+yCtpfUdgqU2hzEGK3j OMpaRT/Yiw0G3m/vV1RCf5Xl1oK5n4Q587r5K2jjOC9vErW93juZY6sOFBaqP+MZok 7EdA7Ui/FblkaCwg16abHqUYqltQJA7CKenmPCbrJteRfvVY/d+b5anez4HgL/09d9 yLGxVuVVc7GjMkopOFdmOp6vT2zV+F4i1Lx9L2gWpSQfJxkLl+Xmb7ViCvcDclCSnF xK8ZrUQ/PlMtQ== Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Internal to mm/gup.c, require that get_user_pages_fast() and __get_user_pages_fast() identify themselves, by setting FOLL_GET. This is required in order to be able to make decisions based on "FOLL_PIN, or FOLL_GET, or both or neither are set", in upcoming patches. Acked-by: Kirill A. Shutemov Reviewed-by: Jan Kara Signed-off-by: John Hubbard --- mm/gup.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index e5f75e886663..c8affbea2019 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2390,6 +2390,14 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, unsigned long len, end; unsigned long flags; int nr = 0; + /* + * Internally (within mm/gup.c), gup fast variants must set FOLL_GET, + * because gup fast is always a "pin with a +1 page refcount" request. + */ + unsigned int gup_flags = FOLL_GET; + + if (write) + gup_flags |= FOLL_WRITE; start = untagged_addr(start) & PAGE_MASK; len = (unsigned long) nr_pages << PAGE_SHIFT; @@ -2415,7 +2423,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, if (IS_ENABLED(CONFIG_HAVE_FAST_GUP) && gup_fast_permitted(start, end)) { local_irq_save(flags); - gup_pgd_range(start, end, write ? FOLL_WRITE : 0, pages, &nr); + gup_pgd_range(start, end, gup_flags, pages, &nr); local_irq_restore(flags); } @@ -2454,7 +2462,7 @@ static int internal_get_user_pages_fast(unsigned long start, int nr_pages, int nr = 0, ret = 0; if (WARN_ON_ONCE(gup_flags & ~(FOLL_WRITE | FOLL_LONGTERM | - FOLL_FORCE | FOLL_PIN))) + FOLL_FORCE | FOLL_PIN | FOLL_GET))) return -EINVAL; start = untagged_addr(start) & PAGE_MASK; @@ -2521,6 +2529,13 @@ int get_user_pages_fast(unsigned long start, int nr_pages, if (WARN_ON_ONCE(gup_flags & FOLL_PIN)) return -EINVAL; + /* + * The caller may or may not have explicitly set FOLL_GET; either way is + * OK. However, internally (within mm/gup.c), gup fast variants must set + * FOLL_GET, because gup fast is always a "pin with a +1 page refcount" + * request. + */ + gup_flags |= FOLL_GET; return internal_get_user_pages_fast(start, nr_pages, gup_flags, pages); } EXPORT_SYMBOL_GPL(get_user_pages_fast);